Liquid crystal displays (LCDs) are more and more widely applied in the display field, but a LCD is not self-luminescent. Produced image light source is provided by a backlight module in the LCD. The backlight of the LCD requires uniform and high brightness.
No matter a light-emitting diode (LED) backlight or a cold cathode fluorescent lamp (CCFL) backlight, light emitted by the backlight is a point source or a line source but not a surface source. But when a backlight module adopts a diffusion film, the light can be distributed into a uniform surface light source. When the light runs through a diffusion layer, the result of optical diffusion is obtained by optical phenomena such as refraction and reflection continuously occurring in two media with different refractive indexes.